CN108219039B

CN108219039B - Components and preparation method of spherical alkoxy magnesium particles

Info

Publication number: CN108219039B
Application number: CN201810018023.3A
Authority: CN
Inventors: 李凌云
Original assignee: Weixin Shenzhen Material Technology Co ltd
Current assignee: Weixin Shenzhen Material Technology Co ltd
Priority date: 2018-01-09
Filing date: 2018-01-09
Publication date: 2020-07-21
Anticipated expiration: 2038-01-09
Also published as: CN108219039A

Abstract

The invention discloses a component of spherical alkoxy magnesium particles and a method for preparing the spherical alkoxy magnesium particles. In the invention, a certain amount of hydroxymethyl cellulose or hydroxypropyl cellulose substances are introduced into alcohol or mixed alcohol compounds and are in contact reaction with metal magnesium powder to prepare alkoxy magnesium; the obtained alkoxy magnesium particles have perfect shapes, high sphericity, higher stacking density and uniform and narrow particle size distribution. Meanwhile, the alkoxy magnesium particles can be used for preparing olefin polymerization catalysts.

Description

Components and preparation method of spherical alkoxy magnesium particles

Technical Field

The invention relates to the field of preparation of alkoxy magnesium, in particular to a component of spherical alkoxy magnesium particles and a method for preparing the spherical alkoxy magnesium particles by using the component.

Background

As is well known, with the development of economy, the demand of polyolefin materials is higher and higher nowadays, and the high-efficiency polyolefin catalyst for producing polyolefin materials is widely applied in the field of polyolefin catalysts due to the well-controlled particle morphology and microstructure. The key role is the composition and microstructure of the carrier, and the carriers obtained by different methods correspondingly obtain catalysts with different structures and performances.

The use of magnesium alkoxides as supports for high performance catalysts is disclosed in a number of patent documents, and catalysts prepared with magnesium alkoxides supports have significantly higher activity, good hydrogen response and excellent copolymerisation performance. In recent years, there are various methods for preparing magnesium alkoxide reported in published technical literature, and the following methods are mainly used: one is a method in which magnesium metal is reacted with an alcohol in the presence of iodine to obtain spherical or ellipsoidal magnesium diethoxide as disclosed in Japanese patent laid-open Nos. 03-74341 and 04-368391, however, it is difficult to control the reaction rate appropriately, the obtained product is inevitably produced in the form of non-uniform large particles or fine powder, and the bulk density is generally low; another method is a spray drying process of diethoxymagnesium alcohol solution disclosed in Japanese patent laid-open No. 6-8733, which can prepare spherical particles and then perform decarboxylation treatment, and the process is complicated and expensive, and the obtained product is difficult to decarboxylate completely, and the product quality is difficult to meet the downstream use; in addition, there is a method in which magnesium metal is reacted with alcohol to obtain magnesium alkoxide, and then the magnesium alkoxide is mechanically ground to control the particle size, and this method has a problem in that the obtained product has non-uniform particle size, which seriously affects the use.

The invention aims to overcome the defects in the prior art and obtain regular spherical alkoxy magnesium particles with good morphology by adopting a simpler and more practical preparation method.

Disclosure of Invention

In view of the problems in the prior art, the invention aims to provide a component of spherical alkoxy magnesium particles, the spherical alkoxy magnesium particles prepared by the component have perfect shapes, high sphericity, higher bulk density of the particles, the bulk density of the particles is more than or equal to 0.30g/m L, the particles have uniform particle size distribution which is less than or equal to 1.2, and the component can be used as a carrier for preparing an olefin polymerization catalyst.

In order to achieve the purpose, the invention adopts the following technical scheme:

a composition of spherical magnesium alkoxide particles, the composition comprising the following components: metal magnesium powder, alcohol or mixed alcohol compounds, iodine simple substance and hydroxymethyl cellulose or hydroxypropyl cellulose.

Furthermore, the molar ratio of the alcohol or mixed alcohol compound to the metal magnesium powder is 2-40, the molar ratio of the iodine simple substance to the metal magnesium powder is 0.0001-0.2, and the proportion of the hydroxymethyl cellulose or the hydroxypropyl cellulose added into the alcohol or mixed alcohol compound is 0.001-500 g/L.

Further, the alcohol or mixed alcohol compound is shown as a general formula R¹OH, wherein R is¹Is C₁～C₂₀The hydrocarbon group of (b) may be a saturated or unsaturated linear, branched or cyclic chain.

Further, the alcohol or mixed alcohol compound includes, but is not limited to, a mixture of one or more of methanol, ethanol, isopropanol, n-butanol, n-hexanol, isooctanol, benzyl alcohol, and phenethyl alcohol.

Further, the molar ratio of the alcohol or mixed alcohol compound to the metal magnesium powder is as follows: 4 to 30.

Further, the molar ratio of the iodine simple substance to the metal magnesium powder is as follows: 0.001 to 0.1.

Further, the proportion of the hydroxymethyl cellulose or the hydroxypropyl cellulose added with the alcohol or the mixed alcohol compound is 0.01-200 g/L.

A method of making spherical magnesium alkoxide particles, the method comprising: under the protection of inert gas, dissolving the hydroxymethyl cellulose or the hydroxypropyl cellulose in the alcohol or the mixed alcohol compound, dissolving the iodine simple substance in the alcohol or the mixed alcohol compound, adding the metal magnesium powder, and heating to the reflux temperature to maintain the reaction until no gas is generated; and washing and drying the solid product generated by the reaction to obtain the alkoxy magnesium particles.

Further, the spherical magnesium alkoxide particles prepared by the method have an average particle diameter of 15 to 120 microns and a particle size distribution Span ═ d90 to d10)/d50 of less than or equal to 1.2.

Further, the spherical magnesium alkoxide particles produced by the method have a bulk density greater than or equal to 0.30g/m L.

The invention has the following beneficial technical effects:

1. the reaction material composition is simple, and the production cost is favorably reduced;

2. after hydroxymethyl cellulose or hydroxypropyl cellulose is introduced, the obtained large particles and fine powder of the alkoxy magnesium particles are fewer, and the particle size distribution is narrower;

3. the alkoxy magnesium has perfect particle shape, good particle sphericity and suitable composition and structure for being used as a carrier of an olefin polymerization catalyst.

Detailed Description

Hereinafter, embodiments of the present invention will be described in further detail with reference to examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

The invention provides a spherical alkoxy magnesium particle component, which comprises metal magnesium powder, an alcohol or mixed alcohol compound, an iodine simple substance and hydroxymethyl cellulose or hydroxypropyl cellulose, wherein the molar ratio of the alcohol or mixed alcohol compound to the metal magnesium powder is 2-40, preferably 4-30, when the adding amount of the alcohol or mixed alcohol compound is too small, the viscosity of a reaction system can be rapidly increased and cannot be effectively and uniformly dispersed, so that the generated particles are poor, when the amount of the alcohol or mixed alcohol compound is too large, the stacking density of the generated alkoxy magnesium particles is generally low, the strength of the particles is also poor, and the performance of a subsequent catalyst is not favorably improved.

In the method for preparing the magnesium alkoxide particles, the shape of the used magnesium metal powder particles is not strictly limited, but the powder with the average particle size of 5-350 microns, preferably 20-200 microns is required, so that the average particle size of the generated magnesium alkoxide particles is controlled to be 15-120 microns, the reactivity of the particles can be ensured to be relatively uniform, and the particle shape of the magnesium alkoxide particles is relatively perfect and uniform.

The alcohol or mixed alcohol compound of the invention is shown as the general formula R¹OH, wherein R is¹Is C₁～C₂₀The hydrocarbon group of (b) may be a saturated or unsaturated linear, branched or cyclic chain; the alcohol or mixed alcohol compound includes but is not limited to one or more of methanol, ethanol, isopropanol, n-butanol, n-hexanol, isooctanol, benzyl alcohol, and phenethyl alcohol; ethanol is preferred. In order to ensure the excellent performance of the prepared alkoxy magnesium, the water content in the alcohol is preferably as low as possible, generally controlled to be less than 1000ppm, preferably less than 200 ppm.

The order of adding the reaction raw materials in the method for preparing the spherical alkoxy magnesium particles is not strictly specified, and can be determined according to needs. The magnesium powder can be added at one time or added in batches, the reaction rate can be controlled well by adding in batches, the reaction can be carried out at 0-100 ℃, generally, the reaction rate is faster when the temperature is higher, and the reaction is better controlled at the reflux temperature. The reaction time is generally 1 to 20 hours, preferably 2 to 10 hours, until no gas is generated. The solid product after the reaction may be washed several times with a mixed alcohol before the reaction or ordinary ethanol (water content less than 200ppm), or may be washed with an inert organic solvent such as hexane, toluene, etc., and then dried to obtain magnesium alkoxide particles. The whole process is completed under the protection of inert gas, wherein the inert gas is helium, argon or nitrogen, and the nitrogen is preferably used in the invention.

The invention will be further illustrated with reference to specific examples:

example 1

Fully replacing a reactor with high-purity nitrogen, sequentially adding 0.1 g of hydroxymethyl cellulose, 20 ml of absolute ethyl alcohol and 0.1 g of iodine under the protection of nitrogen, stirring to dissolve, heating, adding 1.0 g of 80-150-mesh magnesium powder and 10 ml of absolute ethyl alcohol, maintaining reflux reaction, adding 1.0 g of 80-150-mesh magnesium powder and 10 ml of absolute ethyl alcohol again at intervals of 20 minutes, adding 4.0 g of magnesium powder and 55 ml of absolute ethyl alcohol in 4 times, maintaining reflux reaction for 4 hours after materials are added, washing twice with absolute ethyl alcohol, wherein the amount of absolute ethyl alcohol is 80 ml each time, washing twice with hexane, the amount of hexane is 100 ml each time, and drying to obtain off-white solid flowable powder after washing is finished, wherein specific results are shown in table 1.

Example 2

This example differs from example 1 only in that: "0.1 g of hydroxymethylcellulose" in example 1 was adjusted to "0.4 g of hydroxymethylcellulose".

Example 3

This example differs from example 1 only in that: the "0.1 g of iodine" in example 1 was adjusted to "0.4 g of iodine".

Example 4

This example differs from example 1 only in that: the "20 ml of absolute ethanol" in example 1 was adjusted to "50 ml of absolute ethanol".

Example 5

This example differs from example 1 only in that: the "0.1 g of hydroxymethyl cellulose" in example 1 was adjusted to "0.1 g of hydroxypropyl cellulose".

Comparative example 1

Fully replacing a reactor with high-purity nitrogen, sequentially adding 15 ml of absolute ethyl alcohol and 0.15 g of iodine under the protection of nitrogen, stirring to dissolve, heating, adding 1.0 g of 80-150-mesh magnesium powder and 10 ml of absolute ethyl alcohol, maintaining a reflux reaction, adding 1.0 g of 80-150-mesh magnesium powder and 10 ml of absolute ethyl alcohol again at intervals of 20 minutes, adding 4.0 g of magnesium powder and 55 ml of absolute ethyl alcohol in 4 times in total, maintaining the reflux reaction for 4 hours after adding materials, washing twice with absolute ethyl alcohol, wherein the amount of absolute ethyl alcohol in each time is 80 ml, washing twice with hexane, the amount of hexane in each time is 100 ml, and drying to obtain off-white solid flowable powder after washing is finished, wherein specific results are shown in table 1.

Example 6

The magnesium alkoxide particles prepared by the invention can be used for synthesizing catalyst components for olefin polymerization: adding 50 ml of titanium tetrachloride into a reactor repeatedly replaced by high-purity nitrogen, cooling to 0 ℃, adding 5g of alkoxy magnesium particles obtained in example 1, slowly heating to 80 ℃, adding 1.5 ml of DIBP (diisobutyl phthalate), continuously heating to 110, maintaining the reaction for 2 hours, then performing pressure filtration on the liquid to be clean, adding 50 ml of titanium tetrachloride again, heating to 110, maintaining the reaction for 2 hours, performing pressure filtration on the liquid to be clean, repeating the process again, washing the obtained solid for 3 times at 50 ℃ by using 100 ml of hexane, and finally drying to obtain solid catalyst powder.

Propylene polymerization, after purging the reactor with high-purity nitrogen gas, 1.5mmol of triethylaluminum and 0.1mmol of diphenyldimethoxysilane were added, 10mg of the above catalyst was further added, and liquid propylene 2.5L and hydrogen 1L (under a standard condition) were added under stirring, and the reaction was maintained at 70 ℃ for 1 hour to obtain 627 g of a polymer having a bulk density of 0.45g/ml and a melt index of 5.29g/10 min.

TABLE 1

As shown in Table 1, the magnesium alkoxide prepared in examples 1 to 5 had a good particle morphology, a high bulk density and a narrow particle distribution, compared to the comparative example. Meanwhile, from the results of example 6, the catalyst prepared by using the magnesium alkoxide particles has high propylene polymerization activity and high bulk density, and is suitable for the production of polypropylene.

The test method involved in the invention is as follows:

1. particle size and distribution of support and catalyst: the MASTERSIZE particle size distribution instrument uses n-hexane as a dispersing agent, and the measuring range is 0.02-2000 mu m. span ═ D (D)₉₀-D₁₀)/D₅₀。

2. Determination of bulk density: DIN-53194.

3. The sphericity of the particles is determined using the CAMSIZER apparatus standard from Retsch, Germany.

The above description is only for the purpose of illustrating the present invention, and it should be understood that the present invention is not limited to the above embodiments, and various modifications conforming to the spirit of the present invention are within the scope of the present invention.

Claims

1. The components of the spherical alkoxy magnesium particles are characterized by comprising metal magnesium powder, alcohol or mixed alcohol, an iodine simple substance and hydroxymethyl cellulose or hydroxypropyl cellulose, wherein the molar ratio of the alcohol or the mixed alcohol to the metal magnesium powder is 2-40, the molar ratio of the iodine simple substance to the metal magnesium powder is 0.0001-0.2, and the proportion of the hydroxymethyl cellulose or the hydroxypropyl cellulose added into the alcohol or the mixed alcohol is 0.01-200 g/L.

2. The composition of spherical magnesium alkoxide particles of claim 1, wherein the alcohol or mixed alcohol is represented by the general formula R1OH, wherein R1 is a C1 to C20 hydrocarbon group, which is a saturated or unsaturated linear, branched or cyclic chain.

3. The composition of spherical alkoxy magnesium particles according to claim 1, wherein the alcohol or mixed alcohol comprises a mixture of one or more of methanol, ethanol, isopropanol, n-butanol, n-hexanol, isooctanol, benzyl alcohol, phenethyl alcohol.

4. The composition of spherical magnesium alkoxide particles as claimed in claim 1, wherein the molar ratio of said alcohol or mixed alcohol to said metallic magnesium powder is: 4 to 30.

5. The composition of spherical alkoxy magnesium particles according to claim 1, wherein the molar ratio of the elementary iodine to the magnesium metal powder is: 0.001 to 0.1.

6. A process for producing spherical magnesium alkoxide particles using the composition of spherical magnesium alkoxide particles as defined in any one of claims 1 to 5, which comprises: under the protection of inert gas, dissolving the hydroxymethyl cellulose or the hydroxypropyl cellulose in the alcohol or the mixed alcohol, dissolving the iodine simple substance in the alcohol or the mixed alcohol, adding the metal magnesium powder, and raising the temperature to the reflux temperature to maintain the reaction until no gas is generated; and washing and drying the solid product generated by the reaction to obtain the alkoxy magnesium particles.

7. The method for preparing spherical magnesium alkoxide particles as claimed in claim 6, wherein the method produces spherical magnesium alkoxide particles having an average particle diameter of 15 to 120 μm and a particle diameter distribution Span = (d90-d10)/d50 of 1.2 or less.

8. The method for preparing spherical magnesium alkoxide particles as claimed in claim 6, wherein the method produces spherical magnesium alkoxide particles having a bulk density of 0.30g/m L or more.